1. Field of the Invention
The present invention relates to semiconductor packaging technology and more particularly, to a stacked MEMS (micro-electromechanical system) microphone packaging method.
2. Description of the Related Art
For the advantages of excellent electrical properties and smaller size, MEMS (Micro-electromechanical Systems) microphones have been getting more and more attention in the field of electro-acoustic. When compared with conventional electrets condenser microphones, MEMS microphones have the advantages of high electrical stability, consistent quality, small package size and ease of the use of SMT (Surface Mount Technology), etc. Therefore, the application of MEMS microphones in the field of acoustics will be more and more widespread.
The commonly known stacked MEMS microphone packaging method is to affix MEMS (Micro-electromechanical Systems) and ASIC (Application-specific Integrated Circuit) to a substrate using a die bonding process, and then to achieve conduction between MEMS/ASIC and an external signal using a wire bonding process, and then to mount a metal shell on the outside for shielding electromagnetic interference. This Stacked MEMS microphone packaging method needs to make a through hole on the metal shell or substrate for the transfer of acoustic signals to MEMS. For example, U.S. Pat. No. 8,115,283 discloses a semiconductor device, entitled “Reversible top/bottom MEMS package”, which has a base substrate having a plurality Of metal traces and a plurality of base vias. An opening is formed through the base substrate. At least one die is attached to the first surface of the substrate and positioned over the opening. A cover substrate has a plurality of metal traces. A cavity in the cover substrate forms side wall sections around the cavity. The cover substrate is attached to the base substrate so the at least one die is positioned in the interior of the cavity. Ground planes in the base substrate are coupled to ground planes in the cover substrate to form an RF shield around the at least one die. The present invention provides a relatively simple method to reduce the degree of difficulty of the manufacturing process and the manufacturing costs.